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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /mm/sparse-vmemmap.c
Initial import
Diffstat (limited to 'mm/sparse-vmemmap.c')
-rw-r--r--mm/sparse-vmemmap.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
new file mode 100644
index 000000000..4cba9c278
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+++ b/mm/sparse-vmemmap.c
@@ -0,0 +1,235 @@
+/*
+ * Virtual Memory Map support
+ *
+ * (C) 2007 sgi. Christoph Lameter.
+ *
+ * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
+ * virt_to_page, page_address() to be implemented as a base offset
+ * calculation without memory access.
+ *
+ * However, virtual mappings need a page table and TLBs. Many Linux
+ * architectures already map their physical space using 1-1 mappings
+ * via TLBs. For those arches the virtual memory map is essentially
+ * for free if we use the same page size as the 1-1 mappings. In that
+ * case the overhead consists of a few additional pages that are
+ * allocated to create a view of memory for vmemmap.
+ *
+ * The architecture is expected to provide a vmemmap_populate() function
+ * to instantiate the mapping.
+ */
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/sched.h>
+#include <asm/dma.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+
+/*
+ * Allocate a block of memory to be used to back the virtual memory map
+ * or to back the page tables that are used to create the mapping.
+ * Uses the main allocators if they are available, else bootmem.
+ */
+
+static void * __init_refok __earlyonly_bootmem_alloc(int node,
+ unsigned long size,
+ unsigned long align,
+ unsigned long goal)
+{
+ return memblock_virt_alloc_try_nid(size, align, goal,
+ BOOTMEM_ALLOC_ACCESSIBLE, node);
+}
+
+static void *vmemmap_buf;
+static void *vmemmap_buf_end;
+
+void * __meminit vmemmap_alloc_block(unsigned long size, int node)
+{
+ /* If the main allocator is up use that, fallback to bootmem. */
+ if (slab_is_available()) {
+ struct page *page;
+
+ if (node_state(node, N_HIGH_MEMORY))
+ page = alloc_pages_node(
+ node, GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT,
+ get_order(size));
+ else
+ page = alloc_pages(
+ GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT,
+ get_order(size));
+ if (page)
+ return page_address(page);
+ return NULL;
+ } else
+ return __earlyonly_bootmem_alloc(node, size, size,
+ __pa(MAX_DMA_ADDRESS));
+}
+
+/* need to make sure size is all the same during early stage */
+void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
+{
+ void *ptr;
+
+ if (!vmemmap_buf)
+ return vmemmap_alloc_block(size, node);
+
+ /* take the from buf */
+ ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);
+ if (ptr + size > vmemmap_buf_end)
+ return vmemmap_alloc_block(size, node);
+
+ vmemmap_buf = ptr + size;
+
+ return ptr;
+}
+
+void __meminit vmemmap_verify(pte_t *pte, int node,
+ unsigned long start, unsigned long end)
+{
+ unsigned long pfn = pte_pfn(*pte);
+ int actual_node = early_pfn_to_nid(pfn);
+
+ if (node_distance(actual_node, node) > LOCAL_DISTANCE)
+ printk(KERN_WARNING "[%lx-%lx] potential offnode "
+ "page_structs\n", start, end - 1);
+}
+
+pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
+{
+ pte_t *pte = pte_offset_kernel(pmd, addr);
+ if (pte_none(*pte)) {
+ pte_t entry;
+ void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
+ if (!p)
+ return NULL;
+ entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
+ set_pte_at(&init_mm, addr, pte, entry);
+ }
+ return pte;
+}
+
+pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
+{
+ pmd_t *pmd = pmd_offset(pud, addr);
+ if (pmd_none(*pmd)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, node);
+ if (!p)
+ return NULL;
+ pmd_populate_kernel(&init_mm, pmd, p);
+ }
+ return pmd;
+}
+
+pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node)
+{
+ pud_t *pud = pud_offset(pgd, addr);
+ if (pud_none(*pud)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, node);
+ if (!p)
+ return NULL;
+ pud_populate(&init_mm, pud, p);
+ }
+ return pud;
+}
+
+pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
+{
+ pgd_t *pgd = pgd_offset_k(addr);
+ if (pgd_none(*pgd)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, node);
+ if (!p)
+ return NULL;
+ pgd_populate(&init_mm, pgd, p);
+ }
+ return pgd;
+}
+
+int __meminit vmemmap_populate_basepages(unsigned long start,
+ unsigned long end, int node)
+{
+ unsigned long addr = start;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ for (; addr < end; addr += PAGE_SIZE) {
+ pgd = vmemmap_pgd_populate(addr, node);
+ if (!pgd)
+ return -ENOMEM;
+ pud = vmemmap_pud_populate(pgd, addr, node);
+ if (!pud)
+ return -ENOMEM;
+ pmd = vmemmap_pmd_populate(pud, addr, node);
+ if (!pmd)
+ return -ENOMEM;
+ pte = vmemmap_pte_populate(pmd, addr, node);
+ if (!pte)
+ return -ENOMEM;
+ vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
+ }
+
+ return 0;
+}
+
+struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
+{
+ unsigned long start;
+ unsigned long end;
+ struct page *map;
+
+ map = pfn_to_page(pnum * PAGES_PER_SECTION);
+ start = (unsigned long)map;
+ end = (unsigned long)(map + PAGES_PER_SECTION);
+
+ if (vmemmap_populate(start, end, nid))
+ return NULL;
+
+ return map;
+}
+
+void __init sparse_mem_maps_populate_node(struct page **map_map,
+ unsigned long pnum_begin,
+ unsigned long pnum_end,
+ unsigned long map_count, int nodeid)
+{
+ unsigned long pnum;
+ unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
+ void *vmemmap_buf_start;
+
+ size = ALIGN(size, PMD_SIZE);
+ vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
+ PMD_SIZE, __pa(MAX_DMA_ADDRESS));
+
+ if (vmemmap_buf_start) {
+ vmemmap_buf = vmemmap_buf_start;
+ vmemmap_buf_end = vmemmap_buf_start + size * map_count;
+ }
+
+ for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
+ struct mem_section *ms;
+
+ if (!present_section_nr(pnum))
+ continue;
+
+ map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
+ if (map_map[pnum])
+ continue;
+ ms = __nr_to_section(pnum);
+ printk(KERN_ERR "%s: sparsemem memory map backing failed "
+ "some memory will not be available.\n", __func__);
+ ms->section_mem_map = 0;
+ }
+
+ if (vmemmap_buf_start) {
+ /* need to free left buf */
+ memblock_free_early(__pa(vmemmap_buf),
+ vmemmap_buf_end - vmemmap_buf);
+ vmemmap_buf = NULL;
+ vmemmap_buf_end = NULL;
+ }
+}